We propose to investigate the fine structure of normal and pathological human olfactory epithelia utilizing scanning electron microscopy (SEM), conventional transmission electron microscopy (TEM), and high voltage electron microscopy (HVEM). Our objectives are to obtain a detailed description of the surface topography and cellular substructure of: 1) functionally normal human olfactry epithelia; 2) functionally abnormal olfactory epithelia from a variety of dysosmic patients; and 3) developing and aging olfactory epithelia. The primary purpose of this study is to obtain structural correlates of olfactory function in normal and pathological tissue and to observe ultrastructural changes involved in growth, development and aging of the olfactory mucosa. It is most probable that functional classes of olfactory pathologies (dysosmias) are causally related to specific classes of lesions in olfactory epithelia that are detectable by electron microscopy. The proposed researches will contribute toward understanding of the functional mechanism of olfaction, provide a data-base of histopathology at the level of the electron microscope, and will improve our understanding--and hopefully treatment--of olfactopathies.